What's the Kennection? #208

What battle, fought 25 miles east of Athens in 490 BC, kept the Persians out of Greece for ten years?

What Chicago rapper won an Oscar in 2015 for the song "Glory," which he recorded with John Legend for the Selma soundtrack?

What elderly nickname has been the title of biographies of both Louis Armstrong and baseball legend Willie Stargell?

What medieval term for brown bears did UCLA adopt as its new team name, replacing "Grizzlies," in 1926?

By 2011, what grassroots political movement had 60 members in its Congressional caucus, founded by Michele Bachmann?

What's the "Kennection"?